A team of astronomers has identified an Earth-like planet orbiting a white dwarf star located 4,000 light years away in the constellation Sagittarius. This rocky planet, comparable in mass to Earth, presents potential insights into the future of our planet as the sun approaches its final stages.
The findings suggest that Earth might escape destruction when the sun expands into a red giant, which could allow for human migration to the outer solar system. Moons such as Europa, Callisto, and Ganymede around Jupiter, as well as Enceladus near Saturn, may become viable habitats for future generations.
Published in Nature Astronomy, the study led by researchers from the University of California, Berkeley, utilized the Keck Telescope in Hawaii to observe the system designated KMT-2020-BLG-0414. This system consists of a white dwarf star and an Earth-sized planet orbiting at a distance twice that of Earth's orbit around the sun. Additionally, a brown dwarf, approximately 17 times the mass of Jupiter, is present in the system.
The research supports the theory that as the sun expands, its loss of mass could push planets into more distant orbits, possibly allowing Earth to avoid being engulfed. Jessica Lu, an associate professor of astronomy at UC Berkeley, emphasized the uncertainty of whether life can endure during this transition. However, she noted that it is crucial for Earth to remain outside the sun's reach during its red giant phase.
Keming Zhang, the lead author of the study, stated that there is no consensus on whether Earth can avoid being consumed by the sun in six billion years. He also pointed out that Earth will remain habitable for only another billion years due to the impending greenhouse effect, which will vaporize the oceans long before the sun's expansion becomes a threat.
As the sun evolves, the habitable zone of the solar system will shift outward, potentially allowing for life to thrive on the moons of Jupiter and Saturn. Zhang suggested that humanity might find refuge in these distant ocean worlds.